1. Field of the Invention
The present invention relates to a heater-attached alkali-encapsulated cell and an alkali laser apparatus.
2. Related Background Art
In the field of laser machining such as welding and cutting with a laser beam, there is a demand for a highly-efficient, compact, and inexpensive laser with high output power and high beam quality. An example of the well-known techniques is to condense high-power laser light from a stack of semiconductor laser diode arrays by a lens or the like and use the condensed light. Another known example is to use a high-power laser beam from a solid-state laser pumped by a semiconductor laser.
However, the laser light emitted from the semiconductor laser diode arrays has the problems that its spectral width broadens and that its beam quality is inferior to those of the conventional lamp-pumped Nd:YAG laser and CO2 laser. In the case of the solid-state laser, its laser medium is a solid and it poses the problems such as appearance of refraction index distribution or strain in the medium due to heat or heterogeneity of heat.
In order to solve these problems, alkali metal vapor lasers (hereinafter referred to simply as alkali lasers) are being studied (e.g., cf. Patent Document 1 and Non-patent Documents 1-4). In the alkali lasers, an alkali metal vapor is generated in an alkali-encapsulated cell in which an alkali metal and a buffer gas are encapsulated, by heating the cell with a heater, and it is used as a laser medium. Since the alkali vapor lasers generate less heat in the medium than the solid-state lasers, the problems due to heat are overcome.    [Patent Document 1] U.S. Pat. No. 6,643,311    [Non-patent Document 1] W. F. Klupke et al., Optics Letters, Vol. 28, 2336 (2003)    [Non-patent Document 2] W. F. Klupke et al., Proc. SPIE, 5448 (2004)    [Non-patent Document 3] R. J. Beach et al., Advanced Solid-State Photonics WC4 (2004)    [Non-patent Document 4] R. J. Beach et al., J. Opt. Soc. Am B 21, 2151 (2004)